The Kiwi Ears Belle is 32Ω at 103.0 dB (no reference unit printed); the Kiwi Ears Halcyon is 29Ω at 109.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The Belle needs 6.0 dB more than the Halcyon to reach the same loudness — 0.50 mW against 0.13 mW.
| Specification | Belle | Halcyon |
|---|---|---|
| Impedance | 32 Ω | 29 Ω |
| Sensitivity | 103.0 dB | 109.0 dB/mW |
| Sensitivity (voltage) | 117.9 dB/V | 124.4 dB/V |
| Power for 100 dB | 0.50 mW | 0.13 mW |
| Voltage for 100 dB | 0.13 V | 60 mV |
| Current for 100 dB | 4.0 mA | 2.1 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.00 Ω | 3.62 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. Kiwi Ears Belle printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, that model needs far more than the table says. Why the two readings differ by so much.
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
9 sources stay below the audible-hiss threshold with the Belle but cross it with the Halcyon (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 6 more).
280 of the 280 sources here reach 100 dB on both.
The Belle is more demanding than 41% of the 567 non-electrostatic models in this database; the Halcyon than 17%.
| dB SPL | Belle power | Belle voltage | Halcyon power | Halcyon voltage |
|---|---|---|---|---|
| 80 | 5.0 µW | 13 mV | 1.3 µW | 6 mV |
| 85 | 0.02 mW | 23 mV | 4.0 µW | 11 mV |
| 90 | 0.05 mW | 40 mV | 0.01 mW | 19 mV |
| 95 | 0.16 mW | 71 mV | 0.04 mW | 34 mV |
| 100 | 0.50 mW | 0.13 V | 0.13 mW | 60 mV |
| 105 | 1.6 mW | 0.23 V | 0.40 mW | 0.11 V |
| Source | Price | Headroom, Belle | Headroom, Halcyon | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 17.8 dB | 23.3 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 26.0 dB | 32.1 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 23.0 dB | 29.1 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 62 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 62 is the JadeAudio JA11, at $20. It leaves 17.8 dB of headroom on the Belle and 23.3 dB on the Halcyon, its output impedance is 0.5 Ω against a one-eighth limit of 4.00 Ω and 3.62 Ω, and its noise figure puts the hiss floor 17 dB and 11 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| Belle | 20Hz-20kHz | not printed | not printed |
| Halcyon | 10-42kHz | not printed | not printed |
Kiwi Ears prints 20Hz-20kHz for the Belle and 10-42kHz for the Halcyon.
Neither range has a tolerance printed beside it, so a wider range on one sheet is not deeper bass or more treble.
Not a measurement; maker by maker.
Both have a page of their own. In full: Kiwi Ears Belle and Kiwi Ears Halcyon. Each figure on this page is labelled on those pages with where it came from, including the ones Kiwi Ears never published — what that maker publishes, counted.